Scouring rush, or Equisetum hyemale, features bamboo-like dark green stems that look like nothing else – they are ridged vertically, stiff and hollow, according to Helen Hamilton, past president of the John Clayton, Chapter, Virginia Native Plant Society.

Each joint (stem node), ringed with a black band, has a whorl of tiny, scale-like leaves fused into a sheath which ends in teeth with fringes. Lacking familiar leaves, in this plant photosynthesis occurs in these stems. From May through September, some of the stems will produce tiny, pine cone-like fruiting heads at the tips, which contain numerous spores.

This plant is not a rush, nor a fern. Equisetum is the single surviving genus of a class of primitive vascular plants, dating back to 350 million years ago. They are grouped with “fern allies” because, like ferns, they do not have flowers, nor seeds, and reproduce by spores. The only close relatives are the smaller, much-branched plants known as horsetails, according to Helen's news release.

Scouring rush likes medium to wet soils, it will grow in up to 4 inches of standing water, in full sun to part shade, and tolerates a wide range of soils. Growing 3-5 feet tall, this evergreen perennial can be extremely aggressive, spreading by branched, creeping rhizomes. Once established, it is difficult to remove, since any small section of rhizome can sprout a new plant. In the home garden, its growth can be restricted by planting in containers.

Native to nearly every county in Virginia and all over the U.S. and Canada, scouring rush is also native to large portions of Eurasia. It typically occurs in wet woods, moist hillsides and stream banks; locally it is often associated with shell marl outcrops.

With 15 percent silica content, early Americans used the stems for polishing pots and pans, and as sandpaper to give a very fine, satiny finish to wood. The silica is water-soluble and has been used as a tea for bladder ailments. Reported as a substitute for asparagus, the plant can interfere with vitamin B metabolism if eaten in large quantities, and is toxic to livestock.